mineral

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

Hardness: 7 on Mohs scale; Color: Translucent tan to brownish-grey; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Hardness: 7 on Mohs scale
Color: Translucent tan to brownish-grey
Luster: Vitreous to greasy

Identified June 19, 2026More mineral →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 7 on Mohs scale; Color: Translucent tan to brownish-grey; Luster: Vitreous to greasy; Crystal structure: Trigonal/Hexagonal; Cleavage: None (conchoidal fracture); Specific gravity: 2.65.

Formation & geological history

Forms through the crystallization of silica-rich magma or precipitation from hydrothermal veins. It is one of the most abundant minerals in the Earth's crust and can be found in rocks of all geological ages.

Uses & applications

Used extensively in glass manufacturing, electronics (due to piezoelectric properties), construction as an aggregate, and as gemstones or focal points for mineral collectors.

Geological facts

Quartz is the second most abundant mineral in Earth's continental crust. Smoky quartz gets its color from natural irradiation of aluminum impurities within the crystal lattice.

Field identification & locations

Identify in the field by its hardness (will scratch glass), lack of cleavage, and conchoidal (shell-like) fracture patterns. It is found globally in igneous, metamorphic, and sedimentary environments.